Left-Sided Back Pain: Causes, Symptoms, Treatment and When to See a Doctor

Pain on the left side of your back can arise from many different structures.

It may begin after lifting or exercise, gradually develop during prolonged sitting, travel into the leg, or occasionally come from a kidney or another internal organ.

The important point is:

The side of the pain alone does not identify the cause.

At Painacea, the first step is to determine:

• Where exactly the pain is located
• Whether it is muscular, joint-related or nerve-related
• Whether it travels into the leg or another area
• Whether urinary, abdominal or other symptoms are present
• Whether imaging is actually necessary
• Whether rehabilitation, medication or a targeted MIPSI may help

Where Is the Pain?

“Left-sided back pain” can mean pain in several different regions.

Left Upper Back

Pain may be felt:

• Around the shoulder blade
• Between the spine and shoulder blade
• Near the ribs
• Around the upper thoracic spine

Possible causes include muscles, ribs, thoracic joints, referred shoulder or neck pain and, less commonly, internal-organ conditions.

Left Flank

Flank pain is usually felt below the ribs and towards the side of the body.

Possible causes include:

• Muscular pain
• Lower rib pain
• Kidney stones
• Kidney infection

The kidneys lie below the rib cage on either side of the spine.

Left Lower Back

Pain in the lumbar region may arise from:

• Muscles and ligaments
• Intervertebral discs
• Facet joints
• Sacroiliac joint
• Spinal nerves
• Vertebrae
• Hip-related conditions

Common Causes of Left-Sided Back Pain

1. Muscle or Soft-Tissue Pain

Pain can develop after:

• Heavy lifting
• Sudden twisting
• Exercise
• Repetitive activity
• Long periods in one position

Muscular pain may feel:

• Aching
• Tight
• Tender
• Worse with certain movements

Pain related to movement does not, however, prove that the problem is purely muscular.

2. Prolonged Sitting and Movement Habits

Long periods in one position may contribute to muscle fatigue and back discomfort.

Rather than blaming one “bad posture,” it is usually more useful to consider:

• How long you remain in one position
• Workstation setup
• Overall physical activity
• Strength and conditioning
• Repetitive loading

3. Herniated or Slipped Disc

A disc herniation may irritate or compress a nearby spinal nerve root.

Symptoms may include:

• Back pain
• Pain travelling into the leg
• Tingling
• Numbness
• Burning or electric pain
• Weakness in more significant cases

Not every disc bulge seen on MRI is responsible for symptoms, and not every disc bulge requires treatment.

4. Facet-Joint Pain

Facet joints are small joints at the back of the spine.

Pain arising from the left lumbar facet joints may be felt predominantly on one side and can sometimes worsen with:

• Standing
• Backward bending
• Rotation
• Changing position

An X-ray or MRI showing facet arthritis does not automatically prove that the joint is causing the pain.

In selected patients, a diagnostic medical branch MIPSI may help clarify whether a facet joint is the pain generator before radiofrequency treatment is considered. NICE recommends radiofrequency denervation only after an appropriate diagnostic medial branch block produces a positive response.

5. Sacroiliac-Joint Pain

The sacroiliac joint connects the pelvis with the lower spine.

Pain is often felt on one side of the lower back or buttock.

It may become more noticeable while:

• Climbing stairs
• Turning in bed
• Standing on one leg
• Getting in or out of a car
• Moving from sitting to standing

Because SI-joint pain can resemble lumbar or hip pain, diagnosis should be based on clinical assessment rather than location alone.

6. Sciatica and Nerve-Root Pain

When a lumbar or sacral nerve root becomes irritated, pain may travel from the lower back or buttock into:

• Thigh
• Calf
• Foot

Symptoms may include:

• Shooting pain
• Burning
• Tingling
• Numbness
• Weakness

7. Kidney Stones or Kidney Infection

Kidney pain is usually felt more towards the flank, beneath the lower ribs, rather than directly over the centre of the lumbar spine.

Kidney stones can cause sharp pain in the back or side that may travel towards the lower abdomen or groin. Blood in the urine, urinary urgency, nausea or painful urination may occur.

Kidney infection may cause:

• Back or flank pain
• Fever or chills
• Frequent or painful urination
• Nausea or vomiting

These symptoms require medical assessment.

8. Vertebral Compression Fracture

A vertebral fracture should be considered particularly when pain begins:

• After trauma
• In someone with osteoporosis
• In an older adult
• After prolonged steroid use
• In someone with certain cancers

Selected painful vertebral compression fractures may be evaluated for vertebroplasty or kyphoplasty, but not every fracture requires a procedure.

9. Abdominal or Internal-Organ Conditions

Less commonly, pain felt in the back can be referred from an internal organ.

For example, pancreatic inflammation typically produces significant upper abdominal pain that may radiate towards the back, rather than simply isolated mild left-sided back pain.

Associated abdominal symptoms should therefore be assessed appropriately rather than assumed to be spinal.

When Is Left-Sided Back Pain an Emergency?

Seek urgent medical attention if back pain is associated with:

• New loss of bladder or bowel control
• Difficulty passing urine
• Numbness around the groin or saddle area
• Sudden or progressively worsening leg weakness
• Severe pain after significant trauma
• Fever with severe back or flank pain
• Known cancer with new severe or progressive back pain
• Rapidly worsening neurological symptoms
• Severe chest or abdominal symptoms

These should not wait for a routine pain-clinic appointment.

How Is Left-Sided Back Pain Diagnosed?

Diagnosis begins with the pattern of pain, not simply the side.

A clinician may assess:

• Exact location
• How the pain started
• Whether movement changes it
• Whether it travels
• Numbness or weakness
• Urinary symptoms
• Abdominal symptoms
• Previous injuries
• Previous treatments
• Relevant medical conditions

Examination may include:

• Spinal movement
• Muscle and joint examination
• Neurological examination
• Hip assessment
• Sacroiliac-joint tests
• Strength, sensation and reflexes

Do You Always Need an MRI?

No.

For uncomplicated acute low-back pain without red flags, routine advanced imaging is generally not appropriate. Imaging becomes more useful when there are neurological findings, trauma, concern for serious disease, persistent symptoms where an intervention or surgery is being considered, or when the result would change management.

If symptoms suggest a kidney or abdominal condition, urine tests, blood tests, ultrasound or CT may sometimes be more relevant than a spinal MRI.

The appropriate investigation depends on what clinical question needs to be answered.

How Is Left-Sided Back Pain Treated?

Treatment should follow the diagnosis.

1. Foundational Treatment

For uncomplicated musculoskeletal pain, treatment may include:

• Remaining active within tolerable limits
• Temporary modification of aggravating activity
• Physiotherapy
• Gradual strengthening and mobility work
• Workstation or ergonomic changes
• Appropriate medication where indicated

The same stretching or strengthening programme should not automatically be prescribed for every patient.

When May MIPSI Help?

MIPSI stands for Minimally Invasive Pain and Spine Interventions.

The Indian Society for the Study of Pain describes MIPSI as a broad group of diagnostic and therapeutic image-guided pain interventions used for appropriately selected spinal, musculoskeletal, neuropathic and other pain conditions.

MIPSI is not required simply because back pain persists.

It may be considered when:

• A specific pain generator is suspected
• Conservative treatment has not provided adequate improvement
• Pain limits rehabilitation or function
• A targeted diagnostic or therapeutic intervention has a clear purpose

Depending on the diagnosis, options may include:

Diagnostic Medial Branch MIPSI

May help confirm whether facet joints are contributing to pain.

Radiofrequency Ablation

May be considered for appropriately diagnosed facet-mediated pain after diagnostic confirmation.

Sacroiliac-Joint MIPSI

May be considered when the sacroiliac joint is identified as an important pain generator.

Epidural or Selective Nerve-Root MIPSI

May be considered for selected patients with nerve-root pain or sciatica.

Spine Endoscopy

Selected disc herniations or nerve-compression conditions may sometimes be suitable for minimally invasive endoscopic treatment.

Vertebroplasty / Kyphoplasty

May be considered for selected painful vertebral compression fractures.

When Is Surgery Needed?

Most left-sided back pain does not require surgery.

Surgical assessment may become appropriate when there is:

• Progressive neurological weakness
• Significant nerve compression
• Structural instability
• A fracture requiring surgical treatment
• Infection or tumour requiring surgical management
• Persistent symptoms from a surgically correctable condition despite appropriate non-surgical care

Painacea’s objective is not to avoid surgery at any cost.

It is to identify which patients can appropriately be treated non-surgically and which patients should be referred for surgical evaluation without unnecessary delay.

When Should You See a Pain Specialist?

Consider specialist evaluation when:

• Pain persists or repeatedly returns
• Pain significantly affects sleep, work or mobility
• Pain travels into the leg
• Numbness or weakness develops
• Medication gives only repeated temporary relief
• Physiotherapy has not produced adequate improvement
• MRI findings and symptoms do not appear to match
• You have been advised a procedure without understanding why
• A specific spinal pain generator needs further assessment

Painacea’s Approach to Left-Sided Back Pain

Painacea is neither medicine-only nor procedure-first.

Our approach is:

Identify where the pain is coming from → rule out important non-spinal causes → correlate symptoms, examination and investigations → use the least invasive appropriate treatment → consider MIPSI when indicated → refer for surgery or another specialty when required.

A first consultation may therefore result in:

• Advice and rehabilitation
• Medication for a defined purpose
• Further investigation
• Referral for kidney or another medical evaluation
• Diagnostic MIPSI
• Therapeutic MIPSI
• Radiofrequency treatment
• Spine endoscopy evaluation
• Surgical referral

Treatment follows diagnosis – not the other way around.